How severe is CVE-2021-39160?

CVE-2021-39160 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-39160?

CVE-2021-39160 affects the following packages: nbgitpuller (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2021-39160?

Update nbgitpuller to 0.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-39160 is resolved across your whole dependency graph.

How do I detect CVE-2021-39160 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nbgitpuller, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-39160 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2021-39160 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-39160 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-39160?

CVE-2021-39160 has an EPSS (Exploit Prediction Scoring System) score of 1.7%, placing it in the 77th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-39160?

CVE-2021-39160 is classified as Code Injection (CWE-94), OS Command Injection (CWE-78). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-39160 published, and has it been updated?

CVE-2021-39160 was published on August 25, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

HIGH severity

CVE-2021-39160 — nbgitpuller

HIGHFix: jupyterhub/nbgitpuller@0769064

CVE-2021-39160 is a high-severity (CVSS 8.8) Code Injection vulnerability in nbgitpuller. A fix is available for nbgitpuller — see the affected versions and patch details below.

Code injection in nbgitpuller

Also known asGHSA-mq5p-2mcr-m52jPYSEC-2021-315

Published

Aug 25, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs77th percentile — riskier than 77% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-39160 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐍nbgitpuller

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Due to an unsanitized input, visiting maliciously crafted links could result in arbitrary code execution in the user environment.

Patches

0.10.2

Workarounds

None, other than upgrade to 0.10.2 or downgrade to 0.8.x.

For more information

If you have any questions or comments about this advisory:

Open an issue in nbgitpuller
Email our security team at [email protected]

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`nbgitpuller`	≥ 0.9.0&&< 0.10.2	0.10.2`pip install --upgrade 'nbgitpuller==0.10.2'`

Affected Products

1 product · 1 configurations

Application

nbgitpullerjupyterhub

≥ 0.9.0 && < 0.10.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nbgitpuller, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nbgitpuller to 0.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-39160 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

### Impact Due to an unsanitized input, visiting maliciously crafted links could result in arbitrary code execution in the user environment. ### Patches 0.10.2 ### Workarounds None, other than upgrade to 0.10.2 or downgrade to 0.8.x. ### For more information If you have any questions or comments about this advisory: * Open an issue in [nbgitpuller](https://github.com/jupyterhub/nbgitpuller/issues) * Email our security team at [[email protected]](mailto:[email protected])